Modern wind turbines are controlled and regulated continuously with the purpose of ensuring optimal power extraction from the wind under the current wind, and weather, while at the same time ensuring that the loads on the different components of the wind turbine are at any time kept within acceptable limits, and while respecting any externally set operational constraints. To accomplish this, a number of parameters are collected and monitored by the controllers in the wind turbine, such as, for instance, the current wind speed and direction, the rotational speed of the rotor, the pitch angle of each blade, the yaw angle, information on the grid system, and measured parameters (e.g. stresses or vibrations) from sensors placed e.g. on the blades, the nacelle, or on the tower. Moreover, external commands may be received via a communication network. Based on this and following some control strategy, control parameters of the turbine are determined in order to perform optimally under the given conditions.
The controller structure of a wind turbine may be implemented in a number of ways. In one type of control system, a number of controller units are used, where each controller unit is in charge of certain operational tasks, ranging from direct control of a given sub-system to set-point calculations based on a number of inputs. In such system, the nature and the complexity of the various control tasks are very diverse, and often also the computational capabilities of the controller units are quite diverse. As a consequence, certain controller unit(s) may act as bottlenecks and restrict other controllers in their ability to support fast reactions to a changing condition.
It is against this background that the invention has been devised.